Mackey was a replicant-sympathizing forensics specialist with the Los Angeles Police Department.
Upon Harper's return after being ambushed by a group of replicants, Mackey asked for a memory cube Harper had found in order to analyze it.[1]
Mackey later explained to Holden and Harper that Night Owl was a viral pathogen developed by Eldon Tyrell in case replicants would ever become a danger to society.[1]